The present invention relates to headphone sets, and, especially, so-called an inner-ear type headphone set to be fit in the auricles of user's ears, equipped with a microphone installed in a headphone housing to pick up ambient sounds.
A noise-canceling headphone set having a noise-canceling function, which is now very popular, is one of the known headphone sets equipped with a microphone installed in a headphone housing to pick up ambient sounds.
One type of the noise-canceling headphone set is equipped with a microphone installed in a headphone housing to pick up ambient sounds through openings made in the housing. When the ambient sounds are picked up, signals are generated as having the reverse phase of the ambient sounds and combined with audio signals to be listened, and output to user's ears via speakers.
The noise-canceling mechanism cancels the ambient sounds almost completely, that pass through the gap between the headphone housing and user's ears or the housing itself to reach the user's ears. With this mechanism, users can enjoy sounds reproduced from audio signals to be listened with almost no effects of the ambient sounds.
With increased use of headphone sets for listening music in daily life, not only an overhead type with a headband to be put on the user's head, but also an inner-ear type to be inserted into the auricles of user's ears has been very popular now, as noise-canceling headphone sets.
The inner-ear type headphone sets include a canal type equipped with a cylindrical sound output tube installed in a headphone housing and attached with a rubber ear piece. The sound output tube is inserted into the canal of a user's ear so that the ear piece touches the inner wall of the canal.
Shown in FIG. 1 is an appearance of a known inner-ear type noise-canceling headphone set.
Installed in a housing 104 are a speaker unit 102 and a microphone 103 aligned along a drive axis CL101 of the speaker unit 102. Provided on the back of the housing 104 are sound pick-up holes 104a through which ambient sounds are picked up by the microphone 103. A sound output tube 105 is attached to the housing 104 as protruding in the opposite direction of the microphone 103.
The sound output tube 105 is covered with an ear piece 106. In use of the headphone set, the ear piece 106 is inserted into the canal of a user's ear so that the housing 104 is attached inside the auricle of the user's ear.
The known inner-ear type noise-canceling headphone set has several disadvantages as discussed below.
The housing 104 is large as indicated by allows L101 in FIG. 1, so that the part of the housing 104 provided with the sound pick-up holes 104a protrudes from a user's ear. This structure allows window noises to be picked up by the microphone 103, thus posing a difficulty in picking up ambient sounds efficiently.
When the window noises are picked up by the microphone 103, the noises could be amplified and output via a speaker, after undergoing a noise-canceling procedure.
The microphone 103 is provided as apart from the ear piece 106, with the speaker 102 interposed therebetween, as shown in FIG. 1. The arrangement has the center of gravity far from the ear piece 106, thus users could not enjoy fitability to his or her ears and the ear piece 106 could easily be out of position due to user body movements.